1. Field of the Invention
The present invention relates to an image projection device.
2. Description of the Related Art
Projectors project enlarged images, such as letters or graphs, and thus are widely used in presentations for a large number of people, etc. In a presentation, the presenter may point an image that is projected on the screen with, for example, a pointer to give explanations easy to follow. However, directly pointing a projected image with a laser pointer has been a problem in that a desired part cannot be pointed accurately due to trembling of the hand. To deal with such a problem, the technology according to Japanese Laid-open Patent Publication No. 11-271675 has been already known in which a built-in CCD (Charge Coupled Device) camera of a projector detects the spot that is illuminated by a user with a laser pointer and a pointer image is displayed on the same spot as the illuminated spot.
However, detection of a spot that is illuminated with a laser pointer from a video image that is captured by a camera in the conventional manner has a problem in that, when the color or luminance of the laser from the laser pointer is similar to the color or luminance of a projected video image, there is a possibility that the laser from the laser pointer cannot be detected depending on the content of projection.
In view of the above-described problem, there is a need to provide an image projection device that can accurately detect a spot that is illuminated by an illuminating device, such as a laser pointer.